The present disclosure generally relates to systems and methods of intershaft sealing in an aircraft engine. More particularly, this disclosure relates to intershaft seal assemblies capable of providing a seal between inner and outer shafts rotatable about a common axis.
At least some known gas turbine engines, such as turbofans, include a fan, a core engine, and a power turbine. The core engine includes at least one compressor, a combustor, and a high-pressure turbine coupled together in a serial flow relationship. More specifically, the compressor and high-pressure turbine are coupled through a shaft to form a high-pressure rotor assembly. Air entering the combustor is mixed with fuel and ignited to form a high energy gas stream. The high energy gas stream flows through the high-pressure turbine to rotatably drive the high-pressure turbine such that the shaft rotatably drives the compressor. The gas stream expands as it flows through a power or low-pressure turbine positioned aft of the high-pressure turbine. The low-pressure turbine includes a rotor assembly having a fan coupled to a drive shaft. The low-pressure turbine rotatably drives the fan through the drive shaft.
The compressor and the turbine are generally coupled through a number of co-axial shafts that include at least one intershaft ring seal assembly. At least some known ring seals are coupled to, and rotate with, the inner shaft. When a ring seal is installed within an intershaft system, the seal exerts a small force onto the inner diameter of the outer shaft. During operation, at least some known ring seals contact the outer shaft and spin within a channel formed in the inner shaft. Radial loads along the ring seal are influenced by the pressure between the shafts and centrifugal forces acting on the seal. Axial loads along the ring seal are influenced by the pressure component.